Method of producing tapers in metal.



L. S. LAGHMAN. METHOD OF PRODUCING TAPERS IN METAL. APPLICATION FILEDrmm, 190a.

Patented Mar. 29, 1910.

2 SHEETS-EHEET 1.

I VVENTOR la are 72 0e 7Zpa Lau h;

ATTORNEYS L. S. LAGHMAN.

METHOD OF PRODUCING PAPERS IN METAL.

APPLICATION FILED PEB.8, 1908.

953,041. Patented M31229, 1910.

. 2 SHEETB-SHEET Z.

' ATTORNEY S.

PATENT OFFICE.

LAURENCE sYLflvA LACHMAN, or NEW YORK, N. 2.. ASSIGNOR T UNIVERSAL ELEC-rma wnmruqoomrany, or NEW YORK, is. Y., A CORPORATION or NEW YORK.

-T0 iZZ' whom 'it may concern:

.Methods of Producing Tapers in 'Metal, of

which the following'is a specification.

-The present invention relates to the process of tapering awrod, bar orother piece of metal to a pointby heating a section of metal. to renderthe same plastic and then applyingstretching or pulling force.

e The special :object of the inventlon 1s,

among other things, to insure the production of a perfectly finishedpoint.

Another "object is to obtain, from asingle bar, rod or piece ofmetaljmtwo tapered pieces which shall be of identical taper.

The invention consists. substantially in heating the piece .of metal:toplasticity by passing a heating. current of electricity through thesame and thennstretching or pulling the, metal of the heated. section totaper the samedown tea-point, the cutting off of flow of heating currentand the-rate of drawingor pulling being so controlled that at theinstant of separation the metal will be at a comparatively lowtemperature.

The invention consists further in stretching or pulling the metalequally in opposite directions to maintain, the position of that portionof the metal which is of smallest section, as hereinafter moreparticularly de-' scribed.

The invention further consists inthe methods or processes andvconstructions of apparatus especially adapted for conducting suchprocesses as hereinafter more particu-' larly described and then recitedin the claims.

In the accompanying drawings, Figure 1 is a side elevation of anapparatus that may be used in carrying out my invention. Fig. 2 is'aplan of the-same and illustrates more directions. Fig. 3 shows the twosimilar pointed pieces resulting from the appllcatlon H j lSpecification of Letters I atent. AppHoa/cionflled February 8, 19oz.Serial No. 414,929.

5 meager) 'o'rrnonuome [PAPERS IN METAL.

Patented Mar. 29,1910.

of the process to a single rod, baror pieceof metal.

1 Referring to the drawings, 1, 1" indicate the guides for two platensor slides 3, 3 mountedupon and electrically joined to the terminals" ofthe secondary 2 of a transformer which supplies heating current to saidplatensan'd to the clamp-holding blocks mounted on the latter. Theplatens l may be attached to flexible terminals of said secondary ormay'slide in contact with the terminals thereof as well understood inthe art.

4 indicates the primary of the transformer and 5 is theline ofseparation or gap between the secondary terminals usually existing inthis type of apparatus, so that the opposite work-holders or clamps onthe clamp blocks 3-, 3 will be located, respectively, at opposite sidesof the gap and the heated section of work will beopposite said up.

Operating levers for tie clamping devices are indicated at 6, 6, while7, 7 indicate the usual clamping jaws adapted to engage and firmly holdthe section of work, as usual in the art of electric welding.

The piece of metal which is to be reduced or tapered to a point isindicated at 8, while the two separate pointed pieces resulting from theoperation are indicated at 8, as shown in Fig. 3.

Incarrying on the process according to my present invention, the bar orrod 8, if it be desired to" form two identical similar pointed piecesfrom it, is clamped in the jaws of the apparatus so that its medial linewill coincide practically with the line -5. If it be desired to producetwo pieces of different lengths, the bar 8 would be shifted so theamount of rearward projection of the ends of the bar would be greater orless as desired. The heating electric current is then turned on, thusbringing the section'of metal between-the clamps to a plastic condition,a proper plasticity in the case of high carbon steel being shown by thecolor being a cherry red. In the case of softer metals, not so high atemperature would be required. When the metal has reached a properdegree of plasticity, a gradual stretching or pulling force is ap liedto the heated section, preferably, t rough the clamps by which theheatlng current is conducted into the work and preferably by moving bothclamps in opposite directions away from one another, thus startin adouble taper toward the center, but be ore or ractically as soon as theulling operation gins the fiow of the heating current is preferablyentirely stopped, thus avoiding the liability to rupture of the heatedsection before it has been drawn down to a point. The rate of pulling isso graduated that at the final stage of rupture the metal will be atacomparatively low temperature, thereby roucing anexceedingly fine sharpoint. or the best results the metal shou d be permitted to cool so farthat at the instant of rupture and immediately before rupture it willhave resumed approximately its natural color or willhave lost itsappearance of in candescence. Such a double motion may be roduced by themechanism to be presently described and is, preferably, an equal motionof both clamps or holders, so that the portion of heated metal ofsmallest section will be maintained incoincidence with the line 5 'ofthe gap in the transformer secondary. By this means the two tapers ofequal degree are secured, whereas, if the motion were given to one clamponly, so as to carry the most reduced portion of the heated section toone side of the line 5, the tapers of the two portions would he ofdifferent degrees. As the tapering progresses and approaches the finalstage of rupture of the metal, at which stage in the operation the metalis at a lower temperature owing to the electric current having been cutoil previously to this sta e being reached, the rate of movement 0 theclamp or clamps, in ap alying the stretching or pulling force, is pre.erably slowed down. The point at which the current should be cut oil,in order to insure the proper degree of cooling when the end of the na lstage is reached, can be varied within limits and also the extent towhich the drawing action is slowed down, but after the metal has beenbrought to the desired degree of plasticity, the surest way is to cutoff the current immediately and before or coincidently with thebeginning of the. drawing or pulling operation.

In Fig. 2 the metalv is shown at the termination of the final stage,which is practically coincident with the rupture of the metal at asection of such minute extent that, in the finished pieces, the taperwill terminate in an extremely fine and well finished point, which, inthe case of tool steel, can be made superior in finish and sharpness toanything that can be produced by an ordinary swaging operation.

The process can be applied to metal of any cross section and may be usedfor producing an edge on a properly shaped piece of metal, said edgebeing, geom'etricall considered, a series of points. In my 0 aims,therefore, while I use the term point it is to be understood that theinvention includes the drawing down or tapering of a piece of metal intoa sharp edge.

The equal opposite movement of the two holders may be secured by anymechanism properly connected up, an exam le of which 15 shown in Fig. 2wherein the c amping devices are shown in section. In this figure, 9 isthe operating handle pivoted at 10 and connected by a link 11 with oneof the clamp supporting blocks or platens, so that, by operating thehandle in the direction of the arrow, tension or stretching or pullingforce may be applied to the heated section. The extension of theoperating handle is connected by a pin with lever 12 and the latter ispositively connected by a connecting rod 13 to the opposite holder ofits operating mechanism, throu h an intermediate lever 14 and link 15.fiy means of this connecting rod and intermediate lever connecting theholders a movement of said holders away from one another in oppositedirections and at an exactly uniform rate is insured under allconditions.

What I claim as my invention is:

1. The improved method of tapering metal to a finished point consistingin passing a heating current of electricity through a section of themetal until the same assumes plasticity, stretching or pulling themetal, and cutting off the flow of current controlling the rate ofpulling, so that at and near the final stage at which rupture takesplace the metal will be at a comparatively low temperature.

2. The herein described method of tapering metal to a point consistingin heating a section of the metal to plasticity by passing an electriccurrent through the same, and drawing or pulling the metal andgraduating the rate of pulling as the metal reaches the final stage ofrupture, so that at and near the point of rupture it willhave resumedapproximately its natural color.

3. The improved method of tapering metal to a point consisting inelectrically heating a section of the metal and stretching or pullingthe metal at an equal rate in opposite directions so as to maintain theposition of the portion of metal which is of the smallest section infixed relation to the fixed portion of the structure, as and for thepurpose described.

4. In an electric. metal working a paratus, the combination ofwork-holders adapted to clamp the work at two points locatedrespectively at opposite sides of the heated section thereof, and arigid system of connecting devices between said holders, whereby any NewYork and State of New York this 4th movement of separation of onework-holder day of February A. D. 1908. away from the other insures anopposite movement of the other work-holder at an LAURENCE SYWAN LACHMAN'5 exactly uniform rate, as and for th purpose Witnesses:

described. Y O. F. TISCHNER, Jr.,

Signed at New York in the county of LILLIAN BLOND.

